Surgery system

ABSTRACT

A surgery system includes an overtube that has a distal end, a proximal end, and a longitudinal axis and holds a treatment tool and an endoscope so as to be movable forward and backward in a direction of the longitudinal axis. The overtube has an endoscope holding part that has an endoscope holding surface for holding the endoscope and allowing circumferential rotation of the endoscope about a central axis of the endoscope, and a treatment tool holding part that has a treatment tool holding surface for holding the treatment tool. The surgery system further includes an endoscope that is inserted into the overtube and has a held surface held by the endoscope holding surface. The endoscope has an orientation maintaining part that maintains the circumferential orientation of the endoscope even in a case where the overtube rotates around the longitudinal axis.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of PCT InternationalApplication No. PCT/JP2016/089150 filed on Dec. 28, 2016 claimingpriority under 35 U.S.C. § 119(a) to U.S. Provisional Application No.62/275,792 filed on Jan. 7, 2016. Each of the above applications ishereby expressly incorporated by reference, in their entirety, into thepresent application.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an endoscope, and a surgery systemhaving an overtube that holds an endoscope and a treatment tool so as tobe movable forward and backward.

2. Description of the Related Art

In recent years, since the invasion to a patient is small compared tosurgery in which a laparotomy, a thoracotomy, or the like is performed,endoscopic surgery using endoscopes (rigid endoscopes), such as alaparoscope, has been widely performed. In the endoscopic surgery, aplurality of holes are made in a patient's body wall, an endoscope isinserted into a body cavity from one hole among the plurality of holes,and a treatment tool is inserted into the body cavity from another hole.Then, treatment of living body tissue is performed with the treatmenttool while displaying endoscopic images obtained by the endoscope on amonitor to observe the living body tissue within the body cavity.

In such endoscopic surgery, an insertion part of the endoscope and aninsertion part of the treatment tool can be inserted into the bodycavity by using an overtube (also referred to as a trocar) having aplurality of insertion passages through which the insertion part of theendoscope and the insertion part of the treatment tool are inserted,respectively (refer to WO2013/176167A). By using the overtube describedthis WO2013/176167A, the number of holes to be made in the patient'sbody wall can be reduced, and the invasion to the patient can besuppressed.

Additionally, the overtube described in WO2013/176167A is insertedthrough an outer sheath (also referred to as a sheathing tube) fixed tothe body wall in a state where the overtube is inserted into the bodycavity and is held by this outer sheath so as to be rotatable around alongitudinal axis. Accordingly, the protruding position of the treatmenttool on an endoscopic image displayed on a monitor can be changed byrotating the overtube relative to the outer sheath.

SUMMARY OF THE INVENTION

Meanwhile, in a case where the overtube is rotated relative to the outersheath in order to change the protruding position of the treatment toolon the endoscopic image, the entire overtube through which the endoscopeand the treatment tool are inserted rotates. For this reason, in a casewhere the endoscope rotates around the longitudinal axis of the overtubeas a center together with the rotation of the overtube, the top andbottom of the endoscopic image displayed on the monitor will change.Thus, a problem occurs in that the endoscopic image becomes difficult tosee.

The invention has been made in view of such circumstances, and an objectthereof is to provide a surgery system that can suppress a change inperspective of an endoscopic image on a monitor even in a case where anovertube has rotated.

A surgery system for achieving the object of the invention comprises anovertube that has a distal end, a proximal end, and a longitudinal axisand holds a treatment tool and an endoscope so as to be movable forwardand backward in the direction of the longitudinal axis. The overtube hasan endoscope holding part that has an endoscope holding surface forholding the endoscope and allowing circumferential rotation of theendoscope about a central axis of the endoscope, and a treatment toolholding part that has a treatment tool holding surface for holding thetreatment tool. The surgery system further comprises an endoscope thatis inserted into the overtube and has a held surface held by theendoscope holding surface. The endoscope has an orientation maintainingpart that maintains the circumferential orientation of the endoscopeeven in a case where the overtube rotates around the longitudinal axis.

According to this surgery system, the change in perspective of theendoscopic image displayed on the monitor can be suppressed even in acase where the overtube rotates around the longitudinal axis.

In the surgery system related to another aspect of the invention, theorientation maintaining part has a rotational moment generation partthat generates a rotational moment around the central axis of theendoscope in a case where the overtube has rotated around thelongitudinal axis, and maintains the orientation of the endoscope usingthe rotational moment generated in the rotational moment generationpart. Accordingly, the change in perspective of the endoscopic imagedisplayed on the monitor can be suppressed even in a case where theovertube rotates around the longitudinal axis.

In the surgery system related to a further aspect of the invention, therotational moment generation part has a biasing member that biases acircumferential position of the endoscope to a fixed position. Therotational moment that maintains the circumferential orientation of theendoscope in a case where the overtube has rotated around thelongitudinal axis can be generated around the central axis of theendoscope by the biasing of the biasing member.

In the surgery system related to a still further aspect of theinvention, the biasing member has a gravity center position at aposition eccentric from the central axis of the endoscope. Accordingly,the rotational moment can be generated around the central axis of theendoscope in a case where the overtube has rotated around thelongitudinal axis.

In the surgery system related to a still further aspect of theinvention, the endoscope has a rigid insertion part inserted into theovertube, a flexible cord part provided on a proximal end side of theinsertion part, a connecting part connecting the insertion part and thecord part to each other, and at least a portion of the connecting partis provided obliquely with respect to a central axis of the insertionpart of the endoscope, and the rotational moment generation part, theconnecting part, and the cord part as the biasing member, and generatesa rotational moment around the central axis of the endoscope with theconnecting part and the cord part in a case where the overtube hasrotated around the longitudinal axis. The rotational moment thatmaintains the circumferential orientation of the endoscope can begenerated around the central axis of the endoscope simply by partiallychanging the configuration of an existing endoscope.

In the surgery system related to a still further aspect of theinvention, the biasing member has a weight member that is provided onthe endoscope, and biases the circumferential position of the endoscopeto a fixed position using the weight of the weight member. Therotational moment that maintains the circumferential orientation of theendoscope can be generated around the central axis of the endoscopesimply by providing the weight member on an existing endoscope.

In the surgery system related to a still further aspect of theinvention, the endoscope has a gravity center position at a positioneccentric from the central axis of the endoscope, and the rotationalmoment generation part generates a rotational moment, resulting fromgravity, about the central axis at the gravity center position of theendoscope. The circumferential orientation of the endoscope can bemaintained using the rotational moment resulting from gravity in a casewhere the overtube has rotated around the longitudinal axis.

In the surgery system related to a still further aspect of theinvention, the overtube has a movable body that is movable in adirection of the longitudinal axis, and the endoscope holding part andthe treatment tool holding part are provided at the movable body.Accordingly, the endoscope and the treatment tool can be moved in aninterlocking manner in the longitudinal axis direction via the movablebody.

In the surgery system related to a still further aspect of theinvention, the movable body has a distal-end-side restricting part thatrestricts movement of the endoscope holding part on a distal end side ofthe movable body, and a proximal-end-side restricting part thatrestricts movement of the endoscope holding part on a proximal end sideof the movable body, and the endoscope holding part is movable betweenthe distal-end-side restricting part and the proximal-end-siderestricting part. Accordingly, the movement of the endoscope holdingpart can be allowed in a range between the distal-end-side restrictingpart and the proximal-end-side restricting part and can be restrictedwithin the range.

A surgery system for achieving the object of the invention comprises anovertube that has a distal end, a proximal end, and a longitudinal axisand holds a treatment tool and an endoscope so as to be movable forwardand backward in a direction of the longitudinal axis. The overtube hasan endoscope holding part that has an endoscope holding surface forholding the endoscope, and a treatment tool holding part that has atreatment tool holding surface for holding the treatment tool. Thesurgery system further comprises an endoscope that is inserted into theovertube and has a held surface held by the endoscope holding surface.The endoscope has a rotational moment generation part that generates arotational moment around the central axis of the endoscope in a casewhere the overtube has rotated around the longitudinal axis. Therotational moment generated in the rotational moment generation part isgreater than a friction moment, about the central axis of the endoscope,resulting from a frictional force between the endoscope holding surfaceand the held surface.

According to this surgery system, a greater rotational moment than thefriction moment is generated even in a case where the overtube rotatesaround the longitudinal axis. Thus, the endoscope can be rotated suchthat the circumferential orientation of the endoscope is maintainedusing this rotational moment.

In the surgery system related to another aspect of the invention, therotational moment generation part has a biasing member that biases acircumferential position about the central axis of the endoscope to afixed position. The rotational moment that maintains the circumferentialorientation of the endoscope in a case where the overtube has rotatedaround the longitudinal axis can be generated around the central axis ofthe endoscope by the biasing of the biasing member.

A surgery system for achieving the object of the invention comprises anovertube that has a distal end, a proximal end, and a longitudinal axisand holds a treatment tool and an endoscope so as to be movable forwardand backward in a direction of the longitudinal axis. The overtube hasan endoscope holding part that has an endoscope holding surface forholding the endoscope, and a treatment tool holding part that has atreatment tool holding surface for holding the treatment tool. Thesurgery system further comprises an endoscope that is inserted into theovertube and has a held surface held by the endoscope holding surface.The endoscope has a gravity center position at a position deviating fromthe central axis of the endoscope. A rotational moment, resulting fromgravity, about the central axis in the gravity center position of theendoscope is greater than a friction moment, about the central axis,resulting from a frictional force between the endoscope holding surfaceand the held surface.

According to this surgery system, the circumferential orientation of theendoscope can be maintained using the rotational moment resulting fromgravity even in a case where the overtube rotates around thelongitudinal axis. Thus, the change in perspective of the endoscopicimage displayed on the monitor can be suppressed.

In the surgery system related to another aspect of the invention, theovertube has a movable body that is movable in a direction of thelongitudinal axis inside the overtube, and the movable body has anendoscope locking part to which the endoscope holding part is locked,and a treatment tool locking part to which the treatment tool holdingpart is locked. The endoscope and the treatment tool can be moved in aninterlocking manner in the longitudinal axis direction.

In the surgery system related to a further aspect of the invention, themovable body has a non-sensing region where the forward and backwardmovement of either the endoscope or the treatment tool does notinterlock with the forward and backward movement of the other and asensing region where the forward and backward movement of either theendoscope or the treatment tool interlocks with the forward and backwardmovement of the other. Hence, since the endoscope does not move forwardand backward with respect to the forward and backward movement operationthereof in a non-sensing region, the range of an observation site, suchas a distal end site of the treatment tool or a body cavity inner site,to be displayed as the endoscopic image on the monitor does not vary,and the size of an image of the observation site can be prevented fromfluctuating in accordance with minute displacement of the treatmenttool. Accordingly, a sense of perspective can be suitably maintained,and a stable endoscopic image can be obtained. Additionally, since theendoscope moves forward and backward with respect to the forward andbackward movement operation in the sensing region, the range of theobservation site that appears in the endoscopic image to be displayed onthe monitor is continuously changed so as to follow the forward andbackward movement of the treatment tool. Since the size of images ofobservation sites other than the distal end site of the treatment toolthat appears in the endoscopic image in accordance with the operation ofthe treatment tool, and the size of the range of the observation sitechanges, the operator can simply obtain a desired image.

The surgery system related to a still further aspect of the inventionfurther comprises an outer sheath that has a distal end opening and aproximal end opening and has an insertion passage through which theovertube is inserted from the proximal end opening so as to be rotatablearound the longitudinal axis. Accordingly, the protruding position ofthe treatment tool on the endoscopic image can be changed by rotatingthe overtube relative to the outer sheath.

A surgery system for achieving the object of the invention comprises anovertube that has a distal end, a proximal end, and a longitudinal axisand holds a treatment tool and an endoscope so as to be movable forwardand backward in a direction of the longitudinal axis. The overtube hasan endoscope holding part that has an endoscope holding surface forholding the endoscope and allowing circumferential rotation of theendoscope about a central axis of the endoscope, and a treatment toolholding part that has a treatment tool holding surface for holding thetreatment tool. The surgery system further comprises an endoscope thatis inserted into the overtube. The endoscope has an insertion part thathas a distal end, a proximal end, and a central axis in a direction ofthe longitudinal axis, a cord part provided on a proximal end side ofthe insertion part, a connecting part that connects the insertion partand the cord part to each other, an image pick-up element provided on adistal end side of the insertion part, a held surface provided at theinsertion part and held by the endoscope holding surface, a rotationalmoment application part that applies a rotational moment around thecentral axis of the insertion part to the image pick-up element. Acenter of gravity of the rotational moment application part is at aposition eccentric from the central axis of the insertion part.

According to this surgery system, the change in perspective of theendoscopic image displayed on the monitor can be suppressed using therotational moment applied from the rotational moment application part tothe image pick-up element even in a case where the overtube rotatesaround the longitudinal axis.

The surgery system of the invention can prevent the change inperspective of the endoscopic image on the monitor even in a case wherethe overtube has rotated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic configuration view of a surgery system of theinvention.

FIG. 2 is an external perspective view of an overtube.

FIG. 3A is an external perspective view illustrating a long tubularovertube part with a long tubular body omitted.

FIG. 3B is an external perspective view of the long tubular overtubepart with the long tubular body omitted, as seen from a directiondifferent from FIG. 3A.

FIG. 4 is an external perspective view of a partition wall member.

FIG. 5 is an external perspective view of a coupling ring thatconstitutes a portion of a slider.

FIG. 6 is a cross sectional view of the overtube and the slider cut in ahorizontal plane, including a longitudinal axis, which is orthogonal toan upward-downward direction.

FIG. 7 is a cross sectional view taken along line “7-7” in FIG. 6.

FIG. 8A is a perspective view illustrating the overtube cut in a planeperpendicular to the longitudinal axis at a position intersecting an armpart extending further toward a proximal end side than a ring part inFIG. 3A.

FIG. 8B is a perspective view illustrating FIG. 8A with the couplingring omitted.

FIG. 8C is a perspective view of the overtube of FIG. 8B as seen from adifferent direction.

FIG. 9 is an illustrative view for illustrating a non-sensing region ofthe coupling ring.

FIG. 10A is an illustrative view for illustrating a sensing region ofthe coupling ring.

FIG. 10B is an illustrative view for illustrating the sensing region ofthe coupling ring together with FIG. 10A.

FIG. 11A is a side view of an endoscope before being inserted into theovertube.

FIG. 11B is a side view of the endoscope after being inserted into theovertube.

FIG. 12 is an external perspective view of the endoscope.

FIG. 13 is an illustrative view for illustrating the gravity centerposition of a biasing member.

FIG. 14A is an illustrative view for illustrating the maintenance of theorientation of the endoscope insertion part around an endoscope centralaxis.

FIG. 14B is an illustrative view for illustrating the maintenance of theorientation of the endoscope insertion part around an endoscope centralaxis together with FIG. 14A.

FIG. 15 is an illustrative view for illustrating individualcircumferential orientations of the endoscope insertion part of theendoscope in a circumferential direction in a case where the overtubehas rotated around the longitudinal axis, and examples of endoscopicimages that are respectively displayed on a monitor in the individualcircumferential orientations of the endoscope insertion part, andreference signs 700 to 702 respectively illustrate the circumferentialorientations of the endoscope insertion part before and after therotation of the overtube and the final orientation of the endoscopeinsertion part.

FIG. 16 is an illustrative view for illustrating the effects of thepresent embodiment and a comparative example, and reference signs 800 tosign 802 illustrate a state before the rotation of the overtube, theeffects of the present embodiment, and the comparative example.

FIG. 17 is a side view of an endoscope of a further Embodiment 1 that isapplicable to the surgery system.

FIG. 18A is an illustrative view for illustrating the gravity centerposition of an endoscope insertion part of an endoscope of the furtherEmbodiment 1.

FIG. 18B is an illustrative view for illustrating generation of arotational moment resulting from a weight member of the endoscope of thefurther Embodiment 1.

FIG. 18C is an illustrative view for illustrating maintenance of theposition and orientation, around the endoscope central axis, of theendoscope insertion part of the endoscope of the further Embodiment 1.

FIG. 19 is an illustrative view for illustrating the generation of arotational moment resulting from gravity in a still further Embodiment2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the invention will be described below in detailaccording to the accompanying drawings. In addition, any of the drawingsmay illustrate main parts in an exaggerated manner for description andmay have dimensions different from actual dimensions.

[Overall Configuration of Surgery System]

FIG. 1 is a schematic configuration view of a surgery system 10 of theinvention. As illustrated in FIG. 1, the surgery system 10 includes anendoscope 100, a treatment tool 200, an overtube 300, and an outersheath 500, and is used for observation, examination, and treatmentwithin a body cavity of a patient.

The endoscope 100 is, for example, a rigid endoscope, such as alaparoscope, and is inserted into the body cavity to observe the insideof the body cavity. The endoscope 100 includes an elongated rigidendoscope insertion part 102 (equivalent to a rigid insertion part ofthe invention) to be inserted into the body cavity, a connecting part103 continuously provided at a proximal end part of the endoscopeinsertion part 102, and a flexible cord part 104 connected to theendoscope insertion part 102 by the connecting part 103. A connector(not illustrated) is provided at an end of the cord part 104 opposite toa side connected to the connecting part 103, and each of a processordevice 108 and a light source device 110 is detachably connected to thecord part via the connector. Additionally, a monitor 112 is connected tothe processor device 108 via a cable.

A distal end part of the endoscope insertion part 102 is provided withan observation part that observes the inside of the patient's bodycavity. The observation part includes an observation window 116 (referto FIG. 12) provided on a distal end surface 114 of the endoscopeinsertion part 102, an illumination unit and an observation opticalsystem (not illustrated) that are provided behind the observation window116, and a solid-state image pick-up element 118 (refer to FIG. 12).

An exit end of a light guide (not illustrated) is disposed at theillumination unit. The light guide is inserted through the endoscopeinsertion part 102, the connecting part 103, and the cord part 104,extends up to the aforementioned connector, and is connected to thelight source device 110. Accordingly, illumination light radiated fromthe light source device 110 is radiated from the illumination unitthrough the light guide to the front of the endoscope insertion part102. Accordingly, the inside of the patient's body cavity isilluminated. In addition, the illumination unit may be provided behindthe illumination window (not illustrated) provided on the distal endsurface 114.

Subject light taken in from the observation window 116 is focused on animage pick-up surface of the solid-state image pick-up element 118(refer to FIG. 12) by the observation optical system, and is convertedinto image pick-up signals by the solid-state image pick-up element 118.A signal cable (not illustrated) connected to the solid-state imagepick-up element 118 is inserted through the endoscope insertion part102, the connecting part 103, and the cord part 104, extends up to theaforementioned connector and is connected to the processor device 108.Accordingly, the processor device 108 displays an endoscopic image 119on the monitor 112 on the basis of the image pick-up signals input fromthe solid-state image pick-up element 118.

The treatment tool 200 is, for example, forceps, and is inserted intothe body cavity to examine or treat an affected part within the bodycavity. The treatment tool 200 includes an elongated treatment toolinsertion part 202 to be inserted into the body cavity, an operatingpart 204 that is provided on a proximal end side of the treatment toolinsertion part 202 and is gripped by an operator, and a treatment part206 that is provided at a distal end of the treatment tool insertionpart 202 and is operable by the operation of the operating part 204.

The treatment tool insertion part 202 is provided with a tubular sheath208, and an operating shaft (not illustrated) that is inserted into thesheath 208 so as to be movable in an axial direction. Additionally, theoperating part 204 is provided with a fixed handle 210, and a movablehandle 214 that is coupled to the fixed handle 210 in a rotationallymovable manner via a rotational movement pin. A proximal end part of theoperating shaft is coupled to the movable handle 214.

The treatment part 206 is provided with a pair of gripping members thatis openable and closable. The gripping members are coupled to a distalend part of the operating shaft via a drive mechanism (not illustrated).With the rotational movement operation of the movable handle 214 of theoperating part 204, the gripping members of the treatment part 206 areopened and closed via the operating shaft and the drive mechanism.

In addition, the treatment tool 200 is not limited to the forceps, andmay be, for example, other treatment tools, such as a laser probe, asuture device, an electric scalpel, a needle holder, an ultrasonicdevice, and an aspirator.

The overtube 300 allows the endoscope insertion part 102 and thetreatment tool insertion part 202 to be inserted thereinto from theproximal end side and delivered from the distal end side. By insertingthe overtube 300 into a body wall, disposing a proximal end side of theovertube outside of the body, and disposing a distal end side of theovertube within the body cavity, the endoscope insertion part 102 andthe treatment tool insertion part 202 are guided into the body cavitywith one overtube 300. Additionally, although the overtube 300 will bedescribed below in detail, the overtube 300 includes an interlockingfunction of moving the endoscope insertion part 102 and the treatmenttool insertion part 202 forward and backward in an interlocking manner.Accordingly, for example, the endoscope insertion part 102 is capable ofbeing moved forward and backward by the forward and backward movementoperation of only the treatment tool insertion part 202, and a suitableendoscopic image 119 is obtained without performing the forward andbackward movement operation of the endoscope insertion part 102.

The outer sheath 500 is formed in a tubular shape, and has a distal endopening 500 a and a proximal end opening 500 b, and an insertion passage(not illustrated) through which the overtube 300 is rotatably insertedaround the longitudinal axis toward the distal end opening 500 a fromthe proximal end opening 500 b. A number of lateral grooves 520 in thecircumferential direction of the outer sheath 500 are provided at anouter peripheral part of the outer sheath 500, and longitudinal grooves504 in a longitudinal axis direction are provided at a plurality ofpoints in the circumferential direction of the outer sheath 500.Accordingly, in a state where the overtube 300 is inserted into the bodywall together with the outer sheath 500, each lateral groove 520restricts the forward and backward movement of the outer sheath 500 withrespect to the body wall, and each longitudinal groove 504 restricts thecircumferential rotation of the outer sheath 500 with respect to thebody wall. Therefore, unintended rotation and forward and backwardmovement of the overtube 300 inserted through the outer sheath 500 withrespect to the body wall are prevented. For this reason, a situation inwhich the position of a distal end of the endoscope insertion part 102fluctuates and an observation visual field unintentionally fluctuates isprevented.

[Configuration of Overtube]

FIG. 2 is an external perspective view of the overtube 300. Asillustrated in FIG. 2, the overtube 300 has an elongated cylindricalshape as a whole, and has an endoscope insertion passage 306 throughwhich the endoscope insertion part 102 is inserted so as to be movableforward and backward along a longitudinal axis 300 a, and a treatmenttool insertion passage 308 through which the treatment tool insertionpart 202 is inserted so as to be movable forward and backward along thelongitudinal axis 300 a. The endoscope insertion passage 306 and thetreatment tool insertion passage 308 are disposed parallel to each otherand are disposed parallel to the longitudinal axis 300 a.

Reference sign “306 a” in the drawing designates an endoscope insertionaxis equivalent to a central axis of the endoscope insertion passage306. Additionally, reference sign “308 a” in the drawing designates atreatment tool insertion axis equivalent to a central axis of thetreatment tool insertion passage 308. In the present embodiment,although the longitudinal axis 300 a, the endoscope insertion axis 306a, and the treatment tool insertion axis 308 a are disposed on the sameplane, these axes are not necessarily disposed on the same plane.

In addition, regarding the position and orientation of a space where theovertube 300 is disposed, terms called “forward”, “backward”, “left”,“right”, “up”, and “down” are used with the orientation from a proximalend surface 302 in a direction along the longitudinal axis 300 a to adistal end surface 304 defined as the forward and with the orientationfrom the longitudinal axis 300 a to the treatment tool insertion axis308 a defined as the right. Hence, for example, the “down” is notnecessarily a vertical direction perpendicular to a horizontal plane,and the “down” become non-parallel to the vertical direction in a casewhere the longitudinal axis 300 a is not parallel to the horizontalplane (refer to FIG. 13).

The proximal end surface 302 of the overtube 300 is provided with afirst proximal end opening 310 that is a proximal end opening thatallows the endoscope insertion part 102 to be inserted into theendoscope insertion passage 306 therethrough, and a second proximal endopening 314 that is proximal end opening that allows the treatment toolinsertion part 202 to be inserted into the treatment tool insertionpassage 308 therethrough. Additionally, the distal end surface 304 ofthe overtube 300 is provided with a first distal end opening 312 that isa distal end opening that allows the endoscope insertion part 102inserted into the endoscope insertion passage 306 to be deliveredforward therethrough, and a second distal end opening 316 that is adistal end opening that allows the treatment tool insertion part 202inserted into the treatment tool insertion passage 308 to be deliveredforward therethrough. That is, the endoscope insertion passage 306allows the first distal end opening 312 and the first proximal endopening 310 to communicate with each other, and the treatment toolinsertion passage 308 allows the second distal end opening 316 and thesecond proximal end opening 314 to communicate with each other.

The overtube 300 is constituted of a long tubular overtube part 320having a shape extending along the longitudinal axis 300 a, a proximalend cap 340 that is attached to a proximal end of the long tubularovertube part 320, and a distal end cap 360 that is attached to a distalend of the long tubular overtube part 320.

The proximal end cap 340 is formed in a columnar shape of which thediameter is made larger than the external diameter of the long tubularovertube part 320 using rigid resins, metals, or the like, and a rearend surface thereof constitutes the aforementioned proximal end surface302. Additionally, the distal end cap 360 is formed of rigid resins,metals, or the like, and a front end surface thereof constitutes theaforementioned distal end surface 304.

The long tubular overtube part 320 has a long tubular body 322 that isformed in an elongated cylindrical shape having the longitudinal axis300 a as central axis using rigid resins, metals, or the like.Additionally, the long tubular overtube part 320 has a slider 400 (referto FIG. 3) that is an interlocking mechanism that moves the endoscopeinsertion passage 306 and the treatment tool insertion passage 308, andthe endoscope insertion part 102 and the treatment tool insertion part202 forward and backward in an interlocking manner in a direction of thelongitudinal axis 300 a (a longitudinal axis direction) within the longtubular body 322.

FIGS. 3A and 3B are external perspective views illustrating the longtubular overtube part 320 with the long tubular body 322 omitted. Asillustrated in FIGS. 3A and 3B, a substantially columnar partition wallmember 324, which extends along the longitudinal axis 300 a, and theslider 400, which is guided by the partition wall member 324 and issupported so as to be movable forward and backward in a forward-backwarddirection are provided within the long tubular body 322.

FIG. 4 is an external perspective view of the partition wall member 324.As illustrated in FIG. 4, the partition wall member 324 is a solidinsulator and extends from the proximal end cap 340 to the distal endcap 360 inside the long tubular body 322. An endoscope guide groove 326and a treatment tool guide groove 328, which extend parallel to thelongitudinal axis 300 a from a proximal end of the partition wall member324 to a distal end thereof, are respectively formed on a side surfaceof the partition wall member 324. The endoscope guide groove 326 forms aportion of the aforementioned endoscope insertion passage 306, and thetreatment tool guide groove 328 forms a portion of the aforementionedtreatment tool insertion passage 308. Additionally, the partition wallmember 324 forms a partition wall between the endoscope insertionpassage 306 and the treatment tool insertion passage 308.

By virtue of the partition wall member 324, the endoscope insertion part102 and the treatment tool insertion part 202 inserted into the overtube300 reliably proceed through the regions of the endoscope insertionpassage 306 and the treatment tool insertion passage 308 correspondingthereto without falling out of the insertion passages, respectively. Forthis reason, the task of inserting the endoscope insertion part 102 andthe treatment tool insertion part 202 into the overtube 300 becomeseasy. Additionally, the contact between the endoscope insertion part 102and the treatment tool insertion part 202 inside the overtube 300 isprevented, and these insertion parts are electrically insulated fromeach other. For that reason, even in a case where the treatment tool 200is one using electricity, generation of electrical leakage(high-frequency electricity or the like) from the treatment tool 200 tothe endoscope 100, electrical noise, or the like can be prevented, anddamage or the like to the endoscope 100 can be prevented in advance.

In addition, the partition wall member 324 may be at least one thatforms a partition wall between the endoscope insertion passage 306 andthe treatment tool insertion passage 308, and may be not necessarily onethat is formed on the basis of a columnar shape, and substantially allregions other than the endoscope insertion passage 306 and treatmenttool insertion passage 308 may be hollow.

Returning to FIGS. 3A and 3B, the slider 400 is externally fitted to anouter peripheral part of the partition wall member 324 inside the longtubular body 322, and is a ring-shaped movable body that is movableforward and backward in the direction of the longitudinal axis 300 awith respect to the partition wall member 324.

FIG. 5 is an external perspective view of a coupling ring 402 thatconstitutes a portion of the slider 400. Additionally, FIG. 6 is a crosssectional view of the overtube 300 and the slider 400 cut in thehorizontal plane, including the longitudinal axis 300 a, which isorthogonal to an upward-downward direction.

As illustrated in FIGS. 3A, 3B, 5, and 6, the slider 400 has anendoscope coupling part 420 (including an endoscope holding part 434 tobe described below) that is disposed inside the endoscope guide groove326, a treatment tool coupling part 422 (including a treatment toolholding part 454 to be described below) that is disposed inside thetreatment tool guide groove 328, and the coupling ring 402 thatintegrally interlocks the endoscope coupling part 420 and the treatmenttool coupling part 422 with each other.

The coupling ring 402 has a tubular ring part 404 that surrounds anouter periphery of the partition wall member 324 in the circumferentialdirection, and an arm part 406. The ring part 404 is in contact with orclose contact with portions other than the endoscope guide groove 326and the treatment tool guide groove 328 in an outer peripheral surfaceof the partition wall member 324. Additionally, the arm part 406 extendsin the forward-backward direction along the treatment tool guide groove328 from the portion of the ring part 404 that faces the treatment toolguide groove 328.

A rear restriction end 408 and a front restriction end 410 that aredisposed to be inserted into the treatment tool guide groove 328 arerespectively provided at a distal end and a proximal end of the arm part406. The rear restriction end 408 and the front restriction end 410 arerespectively provided with openings 408A and 410A through which thetreatment tool insertion part 202 is inserted. Also, the rearrestriction end 408 and the front restriction end 410 restrict theforward and backward movement of the treatment tool coupling part 422 (atreatment tool fixture 450 to be described below), which is disposedinside the treatment tool guide groove 328, in the forward-backwarddirection therebetween. That is, the rear restriction end 408 and thefront restriction end 410 function as a treatment tool locking part ofthe invention.

A flat first engaging part 404A, which is parallel to an opening of theendoscope guide groove 326 and extends in the forward-backwarddirection, is formed at the portion of the ring part 404 that faces theendoscope guide groove 326. The rotation of the coupling ring 402 aroundof the longitudinal axis 300 a (hereinafter abbreviated as “around thelongitudinal axis”) with respect to the partition wall member 324 isrestricted by the first engaging part 404A and the aforementioned rearrestriction end 408 and front restriction end 410. Additionally, anengaging hole 412 to be described below is formed in the first engagingpart 404A.

Also, the coupling ring 402 is supported by the partition wall member324 so as to be movable forward and backward in the forward-backwarddirection, and is supported by the partition wall member 324 in a statewhere the movement of the coupling ring in the upward-downward directionand the rotation of the coupling ring in all directions (directionaround three axes including a forward-backward axis, aleftward-rightward axis), and an upward-downward axis are restricted (astate where at least the rotation of the coupling ring around at leastthe longitudinal axis is impossible). Additionally, the coupling ring402 moves forward and backward within a movable range having a position,where the rear restriction end 408 of the coupling ring 402 abutsagainst the proximal end cap 340, as a rear end, and having a position,where the front restriction end 410 of the coupling ring 402 abutsagainst the distal end cap 360, as a front end.

FIG. 7 is a cross sectional view taken along line “7-7” in FIG. 6. FIG.8A is a perspective view illustrating the overtube 300 cut in a planeperpendicular to the longitudinal axis 300 a at a position intersectingthe arm part 406 extending further toward the proximal end side than thering part 404 in FIG. 3A. FIG. 8B is a perspective view illustratingFIG. 8A with the coupling ring 402 omitted. FIG. 8C is a perspectiveview of the overtube 300 of FIG. 8B as seen from a different direction.

As illustrated in FIGS. 6, 7, and 8A to 8C, the endoscope coupling part420 is disposed within the endoscope guide groove 326, and is coupled(engaged) with the endoscope insertion part 102 inserted into theendoscope guide groove 326. Additionally, the treatment tool couplingpart 422 is disposed within the treatment tool guide groove 328, and iscoupled (engaged) with the treatment tool insertion part 202 insertedinto the treatment tool guide groove 328.

The endoscope coupling part 420 has an endoscope fixture 430 that isdisposed inside the endoscope guide groove 326, and is movable forwardand backward in the forward-backward direction along the endoscopeinsertion passage 306 formed by the endoscope guide groove 326. Theendoscope fixture 430 is constituted of a tubular frame 432 thatapproaches or comes into contact with an inner wall surface of theendoscope guide groove 326, and a tubular endoscope holding part 434,such as an O ring, which is fixed inside the frame 432 and formed ofelastic materials, such as elastic rubber.

The frame 432 has a shape such that the movement (rotation) thereof isimpossible in the direction around the axis inside the endoscope guidegroove 326, and the endoscope fixture 430 is allowed only to moveforward and backward in the forward-backward direction within theendoscope guide groove 326.

An outer peripheral part of the frame 432 is provided with a protrusion436 that protrudes toward the outside of an opening of the endoscopeguide groove 326 at a position that faces the opening. The protrusion436 is inserted through the engaging hole 412, equivalent to anendoscope locking part of the invention, formed in the first engagingpart 404A, and is locked in the forward-backward direction. Accordingly,the relative forward and backward movement of the endoscope fixture 430in the forward-backward direction with respect to the coupling ring 402is restricted. Therefore, the coupling ring 402 and the endoscopefixture 430 integrally move forward and backward in the forward-backwarddirection.

The endoscope holding part 434 has an endoscope holding surface 434 a(refer to FIG. 7) that is brought into pressure contact (engaged) withan outer peripheral surface of the endoscope insertion part 102 insertedtherethrough to hold the endoscope insertion part 102. Accordingly, theendoscope central axis 100 a (refer to FIG. 12), which is a central axisof the endoscope 100 (endoscope insertion part 102), is disposedsubstantially coaxially with the endoscope insertion axis 306 a. Sincethe endoscope holding surface 434 a is brought into pressure contactwith the outer peripheral surface of the endoscope insertion part 102due to an elastic force, the endoscope holding surface 434 a allows thecircumferential rotation of the endoscope 100 about the endoscopecentral axis 100 a. Additionally, the endoscope holding part 434 is ableto randomly adjust the holding position of the endoscope insertion part102 in the forward-backward direction.

Here, such machining processing that a frictional force restricting therotation of the endoscope insertion part 102 becomes smaller than africtional force restricting the movement of the endoscope insertionpart 102 in the forward-backward direction may be performed on theendoscope holding surface 434 a. As this machining processing, forexample, a plurality of lateral grooves (refer to the lateral grooves520 of FIG. 1) are formed in the endoscope holding surface 434 a in acircumferential direction thereof. Accordingly, the rotation of theendoscope insertion part 102 can be allowed, and the movement of theendoscope insertion part 102 in the forward-backward direction can berestricted to some extent.

The treatment tool coupling part 422 has the treatment tool fixture 450that is disposed between the rear restriction end 408 of theaforementioned arm part 406, and the front restriction end 410, insidethe treatment tool guide groove 328. The treatment tool fixture 450 ismovable forward and backward in the forward-backward direction along thetreatment tool guide groove 328 between the rear restriction end 408 andthe front restriction end 410.

The treatment tool fixture 450 is constituted of a tubular frame 452that approaches or comes into contact with an inner wall surface of thetreatment tool guide groove 328, and a tubular treatment tool holdingpart 454, such as O-ring, which is fixed inside the frame 452 and formedof elastic materials, such as elastic rubber. In addition, an innerperipheral surface of the treatment tool holding part 454 is formed in ashape such that regularities are repeated in the circumferentialdirection so as to be appropriately engageable with even treatment toolinsertion parts 202 having a plurality of types of different diameters.

The treatment tool holding part 454 has a treatment tool holding surface454 a that is brought into pressure contact (engaged) with an outerperipheral surface of the treatment tool insertion part 202 insertedtherethrough to hold the treatment tool insertion part 202. Accordingly,the central axis of the treatment tool insertion part 202 is disposedsubstantially coaxially with the treatment tool insertion axis 308 a.Since the treatment tool holding surface 454 a is brought into pressurecontact with the outer peripheral surface of the treatment toolinsertion part 202 due to an elastic force, the holding position of thetreatment tool insertion part 202 in the forward-backward direction canbe randomly adjusted by the treatment tool holding surface 454 a.

The treatment tool fixture 450 also integrally moves forward andbackward in an interlocking manner with the forward and backwardmovement of the treatment tool insertion part 202 in theforward-backward direction (axial direction). In this case, thetreatment tool fixture 450 is movable forward and backward in theforward-backward direction along the treatment tool guide groove 328between the rear restriction end 408 and the front restriction end 410,as mentioned above. That is, the arm part 406 allows the forward andbackward movement of the treatment tool fixture 450 in theforward-backward direction with respect to the coupling ring 402 in arange from a position where the treatment tool fixture 450 abuts againstthe rear restriction end 408 to a position where the treatment toolfixture 450 abuts against the front restriction end 410, and restrictsthe treatment tool fixture 450 in that range.

Additionally, the treatment tool fixture 450 also rotates inside thetreatment tool guide groove 328 in an interlocking manner with therotation of the treatment tool insertion part 202 around the axisthereof.

FIG. 9 is an illustrative view for illustrating a non-sensing region ofthe coupling ring 402. As illustrated in FIG. 9, in a case where a rangewhere the endoscope fixture 430 is movable forward and backward withrespect to the coupling ring 402 is defined as a first range and a rangewhere the treatment tool fixture 450 is movable forward and backwardwith respect to the coupling ring 402 is defined as a second range, thefirst range becomes zero because the forward and backward movement ofthe endoscope fixture 430 in the forward-backward direction with respectto the first engaging part 404A of the coupling ring 402 is restrictedas described above. In contrast, the second range is a range between therear restriction end 408 and the front restriction end 410 as mentionedabove. Accordingly, the coupling ring 402 has a non-sensing region whereeither the treatment tool fixture 450 or the endoscope fixture 430 isnot moved forward and backward (interlocked) with the forward andbackward movement of the other of the treatment tool fixture 450 and theendoscope fixture 430.

Hence, since the endoscope 100 does not move forward and backward withrespect to the forward and backward movement operation of the treatmenttool in the non-sensing region (forward and backward movement in a rangewhere the treatment tool fixture 450 and the rear restriction end 408 orthe front restriction end 410 do not abut against each other), the rangeof an observation site, such as a distal end site of the treatment tool200 and a body cavity inner site, to be displayed on the monitor 112 asan endoscopic image 119 does not vary, and the size of an image of theobservation site can be prevented from fluctuating in accordance withminute displacement of the treatment tool 200. Accordingly, a sense ofperspective can be suitably maintained, and a stable endoscopic imagecan be obtained.

FIGS. 10A and 10B are illustrative views for describing a sensing regionof the coupling ring 402. As illustrated in FIGS. 10A and 10B, in a casewhere the treatment tool fixture 450 has moved forward and backward inthe forward-backward direction or in a case where the coupling ring 402has moved forward and backward in the forward-backward directiontogether with the endoscope fixture 430, the treatment tool fixture 450abuts against the rear restriction end 408 or the front restriction end410. In this state, the coupling ring 402 has a sensing region whereeither the endoscope fixture 430 or the treatment tool fixture 450 ismoved forward and backward movement (interlocked) with respect to theforward and backward movement (the forward and backward movement in adirection in which the treatment tool fixture 450 and the rearrestriction end 408 or the front restriction end 410 are not spacedapart from each other) of other of the endoscope fixture 430 and thetreatment tool fixture 450.

Since the endoscope 100 moves forward and backward with respect to theforward and backward movement operation in the sensing region, the rangeof the observation site that appears in an endoscopic image 119 to bedisplayed on the monitor 112 is continuously changed so as to follow theforward and backward movement of the treatment tool 200. Since the sizesof images of observation sites other than the distal end site of thetreatment tool 200 that appears in the endoscopic image 119 inaccordance with the operation of the treatment tool 200, and the size ofthe range of the observation site changes, the operator can simplyobtain a desired image.

In this way, the slider 400 has the non-sensing region where the forwardand backward movement of either the endoscope insertion part 102 coupledto the endoscope fixture 430 or the treatment tool insertion part 202coupled to the treatment tool fixture 450 in the forward-backwarddirection (axial direction) does not interlock with the forward andbackward movement of the other and the sensing region where the forwardand backward movement of either the endoscope insertion part 102 or thetreatment tool insertion part 202 interlocks with the forward andbackward movement of the other That is, the endoscope insertion part 102is adapted to interlock with the forward and backward movement of thetreatment tool insertion part 202 in the axial direction with play bythe slider 400.

In addition, although the first range where the endoscope fixture 430 ismovable forward and backward with respect to the coupling ring 402 iszero in the present embodiment, the forward and backward movement of theendoscope fixture 430 together with the treatment tool fixture 450 withrespect to the coupling ring 402 or instead of the treatment toolfixture 450 may be allowed, and the first range may have a magnitudeother than zero. Namely, a configuration may be adopted in which theforward and backward movement of at least one of the endoscope fixture430 and the treatment tool fixture 450 with respect to the coupling ring402 is allowed.

Additionally, in a case where the forward and backward movement of theendoscope fixture 430 with respect to the coupling ring 402 is allowed,it is possible to adopt a form in which the range, in theforward-backward direction, of the engaging hole 412 of the firstengaging part 404A to be engaged with the protrusion 436 of theendoscope fixture 430 is increased. In this case, an end part on a frontside of the engaging hole 412 functions as a distal-end-side restrictingpart of the invention that restricts the movement of the endoscopefixture 430 (endoscope holding part 434) on the distal end side of theslider 400, and an end part on a rear side of the engaging hole 412functions as a proximal-end-side restricting part of the invention thatrestricts the movement of the endoscope fixture 430 (endoscope holdingpart 434) on the proximal end side of the slider 400. Accordingly, theendoscope fixture 430 can be made movable forward and backward withrespect to the coupling ring 402 with the length range of the engaginghole 412 in the forward-backward direction as the first range. Moreover,the endoscope fixture 430 can be made movable forward and backward withrespect to the coupling ring 402, using the same configuration(equivalent to the distal-end-side restricting part and theproximal-end-side restricting part of the invention) as the rearrestriction end 408 and the front restriction end 410 of the arm part406 with respect to the treatment tool fixture 450.

Additionally, the endoscope fixture 430 may be rotatable around theendoscope insertion axis 306 a within the endoscope insertion passage306. In that case, the configuration of the arm part 406 of the couplingring 402 with respect to the treatment tool fixture 450 can be adoptedfor the endoscope fixture 430.

In the above embodiment, although the endoscope insertion passage 306(endoscope insertion axis 306 a) and the treatment tool insertionpassage 308 (treatment tool insertion axis 308 a) are parallel to thelongitudinal axis 300 a, these axes may not be necessarily parallel toeach other.

For example, the treatment tool insertion passage 308 may be disposedparallel to the longitudinal axis 300 a, and the endoscope insertionpassage 306 may be disposed obliquely with respect to the longitudinalaxis 300 a. In this case, since the endoscope fixture 430 moves also inthe upward-downward direction with respect to the partition wall member324 and the coupling ring 402 together with the forward and backwardmovement thereof in the forward-backward direction, the protrusion 436formed on the outer peripheral part of the endoscope fixture 430 alsomoves in the upward-downward direction with respect to the coupling ring402 in accordance with the position of the endoscope fixture 430 in theforward-backward direction. Thus, the engaging hole 412 is formed as anelongated hole extending in the circumferential direction(upward-downward direction) within the range of the first engaging part404A or beyond this range.

[Configuration of Endoscope]

FIG. 11A is a side view of the endoscope 100 before being inserted intothe overtube 300, and FIG. 11B is a side view of the endoscope 100 afterbeing inserted into the overtube 300. FIG. 12 is an external perspectiveview of the endoscope 100.

As illustrated in FIGS. 11A, 11B, and 12, the endoscope 100 includes theendoscope insertion part 102, the connecting part 103, and the cord part104 as already described. The endoscope insertion part 102 is providedwith a held surface 102 a that is held by the endoscope fixture 430(endoscope holding surface 434 a of the endoscope holding part 434) soas to be rotatable around the endoscope central axis 100 a (hereinafterabbreviated as “around the endoscope central axis”) in a case where theendoscope insertion part 102 is inserted into the endoscope insertionpassage 306 of the overtube 300.

The connecting part 103 and the cord part 104 function as a biasingmember 111 of the invention that biases the circumferential position ofthe endoscope insertion part 102 to a fixed position in a case where theovertube 300 has been rotated around the longitudinal axis with respectto the outer sheath 500.

A portion of the connecting part 103 is provided obliquely with respectto the endoscope central axis 100 a by being bent with respect to theendoscope insertion part 102. In addition, the bending angle of theconnecting part 103 is not particularly limited. The bending directionof the connecting part 103 with respect to the endoscope insertion part102 (endoscope central axis 100 a) is a downward direction. Asillustrated in FIG. 12, this downward direction is the same (includingsubstantially the same) as a direction b toward a lower-end-side imagepick-up region of the solid-state image pick-up element 118corresponding to a lower end side of the endoscopic image 119 from anupper-end-side image pick-up region of the solid-state image pick-upelement 118 corresponding to an upper end side of the endoscopic image119 displayed on the monitor 112.

FIG. 13 is an illustrative view for illustrating a gravity centerposition SG of the biasing member 111 (the connecting part 103 and thecord part 104). As illustrated in FIG. 13, the gravity center positionSG of the biasing member 111 including the connecting part 103 and thecord part 104 is a position eccentric (spaced apart) by a predetermineddistance X from the endoscope central axis 100 a of the endoscopeinsertion part 102 by bending a portion of the connecting part 103. Inaddition, the gravity center position SG in FIG. 13 is an example, andthe position thereof is not particularly limited.

A biasing force BF resulting from the weight of the cord part 104 isadded to an end part of the connecting part 103 opposite to a sideconnected to the endoscope insertion part 102. Here, since the overtube300, the endoscope 100, and the like are used in a state where these aretitled obliquely downward toward a patient side from the operator duringthe normal treatment of the surgery system 10, the aforementionedgravity center position SG is located below the endoscope central axis100 a from an operator's viewpoint. For this reason, the biasing forceBF acts on the endoscope insertion part 102 from the connecting part 103in a direction in which the endoscope insertion part 102 is pushed intothe endoscope insertion passage 306, and in a direction in which theendoscope insertion part 102 is rotated such that the orientation of abending portion of the connecting part 103 bent with respect to theendoscope central axis 100 a faces downward. As a result, since theendoscope insertion part 102 is held by the endoscope fixture 430 so asto be rotatable around the endoscope central axis, the orientation ofthe bending portion of the connecting part 103 faces downward.

In addition, in the present embodiment, the frictional force thatrestricts the movement of the endoscope insertion part 102 in theforward-backward direction by the endoscope fixture 430 as already aboveis made higher than the frictional force that restricts the rotation ofthe endoscope insertion part 102. Thus, even in a case where the forcehas acted on the endoscope insertion part 102 in the direction in whichthe endoscope insertion part 102 is pushed into the endoscope insertionpassage 306, the forward movement of the endoscope insertion part 102can be restricted. Here, in a case where it is necessary to restrict theforward movement of the endoscope insertion part 102, the forwardmovement of the endoscope insertion part 102 may be restricted byvarious techniques, such as providing a restricting part that restrictsthe forward movement.

In this way, the endoscope insertion part 102 is maintained in anorientation in which the bending portion of the connecting part 103faces downward by the biasing force BF that acts from the cord part 104via the connecting part 103. That is, the orientation of the endoscopeinsertion part 102 around the endoscope central axis is maintained in afixed direction by the connecting part 103 and the cord part 104.

FIGS. 14A and 14B are illustrative views for illustrating themaintenance of the orientation of the endoscope insertion part 102around the endoscope central axis. As illustrated in FIG. 14A, a gravitycenter position TG in a cross section orthogonal to the endoscopecentral axis 100 a of the endoscope insertion part 102 is a position R1that is eccentric downward from the endoscope central axis 100 a becausethe endoscope insertion part 102 receives the action of the biasingforce BF from the connecting part 103 and the cord part 104. Inaddition, the gravity center position TG in the drawing is an example,and any position eccentric downward from the endoscope central axis 100a in accordance with the magnitude of the biasing force BF can be takenas the gravity center position.

As illustrated in FIG. 14B, if the endoscope insertion part 102 hasrotated around the endoscope central axis and the gravity centerposition TG has moved from the position R1 to a certain position R2, arotational moment MR is generated around the endoscope central axis ofthe endoscope insertion part 102 due to the action of the biasing forceBF so as to cancel out this rotation. That is, the connecting part 103and the cord part 104 (biasing member 111) function as a rotationalmoment generation part of the invention.

The rotational moment MR is expressed by MR=Fv×r in a case where adownward component of the biasing force BF (refer to FIG. 13) is definedas a biasing force BF1, a component, which is orthogonal to a linesegment connecting the endoscope central axis 100 a and the gravitycenter position TG, in the biasing force BF1 is defined as Fv, and thedistance of the above line segment is defined as r. In addition,although a component Fp parallel to the above line segment in thebiasing force BF1 also acts on the gravity center position TG, themovement of the endoscope insertion part 102 in a direction parallel tothe above line segment is restricted by the endoscope fixture 430 andthe like.

The rotational moment MR is a value that fluctuates depending on theposition R2. For this reason, in the present embodiment, the magnitudeof the biasing force BF (the length and weight of the cord part 104) anda friction moment Mf is adjusted such that the rotational moment MRbecome greater than a friction moment Mf about the endoscope centralaxis 100 a by a frictional force between the endoscope holding surface434 a and the held surface 102 a, regardless of the position R2.

Therefore, by virtue of the rotational moment MR about the endoscopecentral axis 100 a in the gravity center position TG (position R2), theendoscope insertion part 102 rotatably held by the endoscope fixture 430can be rotated in a reverse direction around the endoscope central axis,and the gravity center position TG can be returned from the position R2to the position R1. Accordingly, the circumferential position of theendoscope insertion part 102 can be biased to the fixed position (aposition of which the gravity center position TG coincides with theposition R1) using the rotational moment MR. As a result, even in a casewhere the overtube 300 has rotated around the longitudinal axis, thecircumferential orientation of the endoscope insertion part 102, thatis, a state where the bending portion of the connecting part 103 facesdownward can be maintained using the rotational moment MR. For thisreason, the connecting part 103 and the cord part 104 (biasing member111) function as an orientation maintaining part of the invention.

Here, the expression “biasing the circumferential position of theendoscope insertion part 102 to the fixed position” or “maintaining thecircumferential orientation of the endoscope insertion part 102” alsoincludes a case where the position and orientation of the endoscopeinsertion part 102 are finally maintained before and after the rotationof the overtube 300 even in a case where a change has temporarilyoccurred in the circumferential position and orientation of theendoscope insertion part 102 due to the rotation of the overtube 300.

In addition, in a case where the rotational moment MR becomessufficiently greater than the friction moment Mf even at the position R2slightly eccentric from the position R1, the endoscope insertion part102 hardly rotates in the circumferential direction even through theovertube 300 rotates around the longitudinal axis, and can alwayssubstantially uniformly maintain the circumferential position andorientation of the endoscope insertion part 102.

[Operation of Surgery System]

Next, the operation of the surgery system 10 of the above configurationwill be described with reference to FIG. 15. FIG. 15 is an illustrativeview for illustrating changes in the circumferential orientation of theendoscope insertion part 102 of the endoscope 100 in a case where theovertube has rotated around the longitudinal axis, and examples ofendoscopic images 119 that are respectively displayed on the monitor 112in the individual circumferential orientations of the endoscopeinsertion part 102. Here, reference sign 700 of FIG. 15 is anillustrative view for describing the circumferential orientation of theendoscope insertion part 102 before the overtube 300 rotates around thelongitudinal axis, and an example of an endoscopic image 119 displayedon the monitor 112 in this circumferential orientation. Reference sign701 of FIG. 15 is an illustrative view for describing thecircumferential orientation of the endoscope insertion part 102 afterthe overtube 300 has rotated around the longitudinal axis, and anexample of an endoscopic image 119 displayed on the monitor 112 in thiscircumferential orientation. Reference sign 702 of FIG. 15 is anillustrative view for describing a final circumferential orientation ofthe endoscope insertion part 102, and an example of an endoscopic image119 displayed on the monitor 112 in this circumferential orientation. Inaddition, in FIG. 15, the outer sheath 500 is illustrated in asimplified manner in order to prevent complication of the drawing.

As illustrated in the illustrative view 700 of FIG. 15, in a case wherethe operator rotates the overtube 300 around the longitudinal axis withrespect to the outer sheath 500 in order to change the protrudingposition of the treatment tool 200 on the endoscopic image 119 displayedon the monitor 112, the gravity center position TG of the endoscopeinsertion part 102 moves from the position R1 to the certain position R2(refer to FIG. 14B). As a result, as illustrated in the illustrativeview 701, the rotational moment MR about the endoscope central axis 100a in the gravity center position TG (position R2) is generated due tothe biasing force BF that acts on the endoscope insertion part 102 fromthe connecting part 103 and the cord part 104.

Since the rotational moment MR becomes greater than the friction momentMf about the endoscope central axis 100 a as already above, asillustrated in the illustrative view 702, the endoscope insertion part102 is rotated in the reverse direction around the endoscope centralaxis due to the rotational moment MR. Accordingly, the circumferentialposition of the endoscope insertion part 102 can be biased to the fixedposition where the gravity center position TG coincides with theposition R1 (refer to FIG. 14B) before and after the rotation of theovertube 300.

Even in a case where the overtube 300 has been rotated around thelongitudinal axis in this way, the circumferential orientation of theendoscope insertion part 102 can be maintained before and after rotationof the overtube 300 such that the bending portion of the connecting part103 is brought into a downwardly facing state. For this reason, theposition and orientation of the solid-state image pick-up element 118around an optical axis (not illustrated) can be maintained. That is, theposition and orientation of the solid-state image pick-up element 118around the optical axis are maintained due to the rotational moment MRapplied from the connecting part 103 and the cord part 104 (biasingmember 111). Therefore, the connecting part 103 and the cord part 104(biasing member 111) function as a rotational moment application part ofthe invention. As a result, a change in perspective of the endoscopicimage 119, which is finally displayed on the monitor 112, before andafter the rotation of the overtube 300, can be suppressed, and the topand bottom of the endoscopic image 119 can be aligned with each other inone direction.

In addition, as already described, in a case where the rotational momentMR becomes sufficiently greater than the friction moment Mf even at theposition R2 slightly eccentric from the position R1, the stateillustrated in the illustrative view 700 is shifted to the stateillustrated in the illustrative view 702 without going through the stateillustrated in the illustrative view 701. In this case, even in a casewhere the overtube 300 is rotated around the longitudinal axis, theendoscope insertion part 102 does not rotate substantially. Thus, thetop and bottom of the endoscopic image 119 displayed on the monitor 112do not change.

[Effects of Present Embodiment]

FIG. 16 is an illustrative view for illustrating the effects of thepresent embodiment and a comparative example. Even in a case where theovertube 300 has rotated around the longitudinal axis from the statebefore the rotation of the overtube 300 as illustrated in anillustrative view 800 in FIG. 16, in the surgery system 10 of thepresent embodiment as illustrated in an illustrative view 801, thecircumferential position and orientation of the endoscope insertion part102 of the endoscope 100 can be maintained. Thus, a change inperspective of the endoscopic image 119 displayed on the monitor 112before and after the rotation of the overtube 300 can be suppressed. Forthis reason, as in a comparative example as illustrated in theillustrative view 802, a situation in which, before and after therotation of the overtube 300, a situation in which the circumferentialposition and orientation of the endoscope insertion part 102 change andthe top and bottom of the endoscopic image 119 displayed on the monitor112 change is prevented. As a result, it is possible to make theendoscopic image 119 displayed on the monitor 112 easier to view thanthe comparative example.

Endoscope of Further Embodiment 1

FIG. 17 is a side view of an endoscope 150 of a further Embodiment 1that is applicable to the above surgery system 10. The endoscope 100 ofthe above embodiment maintaining the circumferential position andorientation of the endoscope insertion part 102 using the rotationalmoment MR generated due to the biasing force BF from the connecting part103 and the cord part 104 in a case where the overtube 300 has rotatedaround the longitudinal axis. In contrast, in the endoscope 150, thecircumferential position and orientation of the endoscope insertion part102 are maintained using a weight member 160.

In addition, the endoscope 150 has basically the same configuration asthe endoscope 100 of the above embodiment except that the endoscope 150includes a pillar-shaped connecting part 153 parallel to the endoscopeinsertion part 102 instead of the connecting part 103 of the aboveembodiment, and the weight member 160 is provided inside the endoscopeinsertion part 102 is removed. For this reason, components having thesame functions and configurations as those of the above embodiment willbe designated by the same reference signs, and the description thereofwill be omitted.

As illustrated in FIG. 17, the weight member 160 is equivalent to thebiasing member of the invention, and is provided downward of theendoscope central axis 100 a inside the endoscope insertion part 102.The weight member 160 adds the biasing force BF, which biases thecircumferential position of the endoscope insertion part 102 to thefixed position, to the endoscope insertion part 102 using the weightthereof, thereby maintaining the position and orientation of theendoscope insertion part 102 around the endoscope central axis. Inaddition, the arrangement and the shape of the weight member 160 are notlimited to the arrangement and the shape that are illustrated in FIG.17, and may be appropriately changed.

FIG. 18A is an illustrative view for illustrating the gravity centerposition of the endoscope insertion part 102 of the endoscope 150 of thefurther Embodiment 1. FIG. 18B is an illustrative view for illustratingthe generation of rotational moment MR resulting from the weight member160 of the endoscope 150 of the further Embodiment 1. FIG. 18C is anillustrative view for illustrating maintenance of the position andorientation, around the endoscope central axis, of the endoscopeinsertion part 102 of the endoscope 150 of the further Embodiment 1. Asillustrated in FIG. 18A, the gravity center position SG of the weightmember 160 is a position eccentric by the predetermined distance Xdownward from the endoscope central axis 100 a of the endoscopeinsertion part 102. For this reason, the gravity center position TG inthe cross section orthogonal to the endoscope central axis 100 a of theendoscope insertion part 102 is also a position eccentric downward fromthe endoscope central axis 100 a. In addition, the gravity centerposition SG and the gravity center position TG in the drawing is anexample, and any position eccentric downward from the endoscope centralaxis 100 a in accordance with to the shape and weight of the weightmember 160, the diameter of the endoscope insertion part 102, or thelike can be taken as the gravity center positions.

As illustrated in FIG. 18B, if the endoscope insertion part 102 hasrotated around the endoscope central axis and the gravity centerposition TG has moved from the position R1 downward of the endoscopecentral axis 100 a to a certain position R2, the rotational moment MR isgenerated around the endoscope central axis of the endoscope insertionpart 102 due to the action of the biasing force BF so as to cancel outthis rotation, similar to the above embodiment. That is, the weightmember 160 functions also as the rotational moment generation part ofthe invention.

The rotational moment MR is expressed by MR=Fv×r, similar to the aboveembodiment illustrated in FIG. 14B as already described. In addition, abiasing force BF1 that is a downward component of the biasing force BFbecomes equal to the biasing force BF in a case where the endoscopecentral axis 100 a of the endoscope insertion part 102 is kepthorizontal. Then, similar to the above embodiment, the weight of theweight member 160 and the magnitude of the friction moment Mf areadjusted such that the rotational moment MR becomes greater than thefriction moment Mf regardless of the position R2.

Therefore, by virtue of the rotational moment MR about the endoscopecentral axis 100 a in the gravity center position TG (position R2), theendoscope insertion part 102 can be rotated in the reverse directionaround the endoscope central axis as in the above embodiment. Thus, thegravity center position TG can be returned from the position R2 to theposition R1 as illustrated in FIG. 18c . Accordingly, thecircumferential position of the endoscope insertion part 102 can bebiased to the fixed position (a position of which the gravity centerposition TG coincides with the position R1) using the rotational momentMR. As a result, even in a case where the overtube 300 has rotatedaround the longitudinal axis, the circumferential orientation of theendoscope insertion part 102 can be maintained in a state where theweight member 160 is located downward of the endoscope central axis 100a. For this reason, the weight member 160 also functions as theorientation maintaining part of the invention. Additionally, since theposition and orientation of the solid-state image pick-up element 118around the optical axis can be maintained using rotational moment MRresulting from the weight member 160, the weight member 160 alsofunctions as the rotational moment application part of the invention.

In addition, for example, in a case where the weight member 160 issufficiently heavy, the rotational moment MR becomes sufficientlygreater than the friction moment Mf regardless of the position R2 as theabove embodiment. Thus, even in a case where the overtube 300 has beenrotated around the longitudinal axis, the circumferential position andorientation of the endoscope insertion part 102 can always besubstantially maintained.

In this way, even in a case where the endoscope 150 of the furtherEmbodiment 1 is applied to the surgery system 10, the circumferentialposition and orientation of the endoscope insertion part 102 can bemaintained in a case where the overtube 300 has been rotated around thelongitudinal axis. Thus, the same effects as those of the aboveembodiment are obtained.

In addition, the weight member 160 may be provided on the outerperipheral surface of the endoscope insertion part 102 within a rangewhere the insertion of the endoscope insertion part 102 into theendoscope insertion passage 306 and the rotation of the endoscopeinsertion part 102 are not hindered instead of being provided inside theendoscope insertion part 102.

Endoscope of Further Embodiment 2

In the endoscope 150 of the above further Embodiment 1, by disposing theweight member 160 within the endoscope insertion part 102, asillustrated in FIGS. 18A to 18C as already described, the gravity centerposition TG of the endoscope insertion part 102 is eccentric downwardfrom the endoscope central axis 100 a. However, the weight member 160 isnot necessary disposed. For example, layout adjustment of variousmembers (the solid-state image pick-up element 118, the observationoptical system, and the like) within the endoscope insertion part 102,adjustment of a cross sectional shape of the endoscope insertion part102, or the like may be performed, and the gravity center position TGmay be eccentric downward from the endoscope central axis 100 a.

In this case, as illustrated in FIG. 19, the endoscope insertion part102 itself functions as the rotational moment generation part, theorientation maintaining part, and the rotational moment application partof the invention, and generates the rotational moment MR, resulting fromgravity G, about the endoscope central axis 100 a in a case where theovertube 300 has been rotated around the longitudinal axis in thegravity center position TG. In addition, FIG. 19 is an illustrative viewfor illustrating the generation of the rotational moment MR resultingfrom gravity G in the further Embodiment 2, and the endoscope centralaxis 100 a will be described herein as being in a horizontal state forsimplification of description.

The rotational moment MR is expressed by MR=Gv x r in a case where acomponent, which is orthogonal to the line segment connecting theendoscope central axis 100 a and the gravity center position TG, ingravity G, is defined as Gv, and the distance of the above line segmentis defined as r. In addition, in a case where the endoscope central axis100 a is not horizontal, Gv, is a component, orthogonal to the aboveline segment, in the downward component of gravity G (refer to FIG. 13).

Additionally, in the further Embodiment 2, the gravity center positionTG (distance r) and the magnitude of the friction moment Mf are adjustedsuch that the rotational moment MR becomes greater than the frictionmoment Mf regardless of the position R2. Accordingly, the endoscopeinsertion part 102 can be rotated around an endoscope central axis inthe reverse direction due to the rotational moment MR, and the gravitycenter position TG can be returned from the position R2 to the positionR1. As a result, similar to the above individual embodiments, even in acase where the overtube 300 has been rotated around the longitudinalaxis, the circumferential position of the endoscope insertion part 102can be biased to the fixed position. As a result, the circumferentialorientation of the endoscope insertion part 102 can be maintained.

[Others]

In the above individual embodiments, the rigid endoscope has beendescribed as an example as the endoscope of the invention. However, theinvention can be applied to various kinds of endoscopes to be used bybeing inserted through the overtube 300.

In the above individual embodiments, the overtube 300 is insertedthrough the outer sheath 500. However, the invention can also be appliedto a case where the overtube 300 directly punctures a body wall withoutbeing inserted through the outer sheath 500.

In the above individual embodiments, the gravity center position TG inthe cross section orthogonal to the endoscope central axis 100 a of theendoscope insertion part 102 is eccentric downward from the endoscopecentral axis 100 a. However, the gravity center position TG may beeccentric in certain directions other than the downward direction fromthe endoscope central axis 100 a.

EXPLANATION OF REFERENCES

-   -   10: surgery system    -   100: endoscope    -   100 a: endoscope central axis    -   102: endoscope insertion part    -   102 a: held surface    -   103: connecting part    -   104: cord part    -   108: processor device    -   110: light source device    -   111: biasing member    -   112: monitor    -   114: distal end surface    -   116: observation window    -   118: solid-state image pick-up element    -   119: endoscopic image    -   150: endoscope    -   153: connecting part    -   160: weight member    -   200: treatment tool    -   202: treatment tool insertion part    -   204: operating part    -   206: treatment part    -   208: sheath    -   210: fixed handle    -   214: movable handle    -   300: overtube    -   300 a: longitudinal axis    -   302: proximal end surface    -   304: distal end surface    -   306: endoscope insertion passage    -   306 a: endoscope insertion axis    -   308: treatment tool insertion passage    -   308 a: treatment tool insertion axis    -   310: first proximal end opening    -   312: first distal end opening    -   314: second proximal end opening    -   316: second distal end opening    -   320: long tubular overtube part    -   322: long tubular body    -   324: partition wall member    -   326: endoscope guide groove    -   328: treatment tool guide groove    -   340: proximal end cap    -   360: distal end cap    -   400: slider    -   402: coupling ring    -   404: ring part    -   404A: first engaging part    -   406: arm part    -   408: rear restriction end    -   408A: opening    -   410: front restriction end    -   410A: opening    -   412: engaging hole    -   420: endoscope coupling part    -   422: treatment tool coupling part    -   430: endoscope fixture    -   432: frame    -   434: endoscope holding part    -   434 a: endoscope holding surface    -   436: protrusion    -   450: treatment tool fixture    -   452: frame    -   454: treatment tool holding part    -   454 a: treatment tool holding surface    -   500: outer sheath    -   500 a: distal end opening    -   500 b: proximal end opening    -   504: longitudinal groove    -   520: lateral groove    -   700 to 702, 800 to 802: illustrative view    -   BF: biasing force    -   BF1: biasing force    -   G: gravity    -   MR: rotational moment    -   Mf: friction moment    -   SG: gravity center position    -   TG: gravity center position    -   X: distance    -   b: direction    -   r: distance cm What is claimed is:

1. A surgery system comprising: an overtube that has a distal end, aproximal end, and a longitudinal axis and holds a treatment tool and anendoscope so as to be movable forward and backward in a direction of thelongitudinal axis, the overtube having an endoscope holding part thathas an endoscope holding surface for holding the endoscope and allowingcircumferential rotation of the endoscope about a central axis of theendoscope, and a treatment tool holding part that has a treatment toolholding surface for holding the treatment tool; and an endoscope that isinserted into the overtube and has a held surface held by the endoscopeholding surface, the endoscope having an orientation maintaining partthat maintains the circumferential orientation of the endoscope even ina case where the overtube rotates around the longitudinal axis, whereinthe orientation maintaining part has a rotational moment generation partthat generates a rotational moment around the central axis of theendoscope in a case where the overtube has rotated around thelongitudinal axis, and maintains the circumferential orientation of theendoscope using the rotational moment generated in the rotational momentgeneration part.
 2. The surgery system according to claim 1, wherein therotational moment generation part has a biasing member that biases acircumferential position of the endoscope to a fixed position.
 3. Thesurgery system according to claim 2, wherein the biasing member has agravity center position at a position eccentric from the central axis ofthe endoscope.
 4. The surgery system according to claim 2, wherein theendoscope has a rigid insertion part inserted into the overtube, aflexible cord part provided on a proximal end side of the insertionpart, a connecting part connecting the insertion part and the cord partto each other, and at least a portion of the connecting part is providedobliquely with respect to a central axis of the insertion part of theendoscope, and wherein the rotational moment generation part has theconnecting part and the cord part as the biasing member, and generates arotational moment around the central axis of the endoscope with theconnecting part and the cord part in a case where the overtube hasrotated around the longitudinal axis.
 5. The surgery system according toclaim 2, wherein the biasing member has a weight member that is providedon the endoscope, and biases the circumferential position of theendoscope to a fixed position using the weight of the weight member. 6.The surgery system according to claim 1, wherein the endoscope has agravity center position at a position eccentric from the central axis ofthe endoscope, and wherein the rotational moment generation partgenerates a rotational moment, resulting from gravity, about the centralaxis at the gravity center position of the endoscope.
 7. The surgerysystem according to claim 1, wherein the overtube has a movable bodythat is movable in a direction of the longitudinal axis, and theendoscope holding part and the treatment tool holding part are providedat the movable body.
 8. The surgery system according to claim 7, whereinthe movable body has a distal-end-side restricting part that restrictsmovement of the endoscope holding part on a distal end side of themovable body, and a proximal-end-side restricting part that restrictsmovement of the endoscope holding part on a proximal end side of themovable body, and the endoscope holding part is movable between thedistal-end-side restricting part and the proximal-end-side restrictingpart.
 9. The surgery system according to claim 8, wherein the movablebody has a non-sensing region where the forward and backward movement ofeither the endoscope or the treatment tool does not interlock with theforward and backward movement of the other and a sensing region wherethe forward and backward movement of either the endoscope or thetreatment tool interlocks with the forward and backward movement of theother.
 10. The surgery system according to claim 1, wherein the overtubehas a movable body that is movable in a direction of the longitudinalaxis inside the overtube, and wherein the movable body has an endoscopelocking part to which the endoscope holding part is locked, and atreatment tool locking part to which the treatment tool holding part islocked.
 11. The surgery system according to claim 1, further comprising:an outer sheath that has a distal end opening and a proximal end openingand has an insertion passage through which the overtube is inserted fromthe proximal end opening so as to be rotatable around the longitudinalaxis.
 12. A surgery system comprising: an overtube that has a distalend, a proximal end, and a longitudinal axis and holds a treatment tooland an endoscope so as to be movable forward and backward in a directionof the longitudinal axis, the overtube having an endoscope holding partthat has an endoscope holding surface for holding the endoscope, and atreatment tool holding part that has a treatment tool holding surfacefor holding the treatment tool; and an endoscope that is inserted intothe overtube and has a held surface held by the endoscope holdingsurface, the endoscope having a rotational moment generation part thatgenerates a rotational moment around the central axis of the endoscopein a case where the overtube has rotated around the longitudinal axis,wherein the rotational moment generated in the rotational momentgeneration part is greater than a friction moment, about the centralaxis of the endoscope, resulting from a frictional force between theendoscope holding surface and the held surface.
 13. The surgery systemaccording to claim 12, wherein the rotational moment generation part hasa biasing member that biases a circumferential position about thecentral axis of the endoscope to a fixed position.
 14. The surgerysystem according to claim 12, wherein the overtube has a movable bodythat is movable in a direction of the longitudinal axis inside theovertube, and wherein the movable body has an endoscope locking part towhich the endoscope holding part is locked, and a treatment tool lockingpart to which the treatment tool holding part is locked.
 15. The surgerysystem according to claim 14, wherein the movable body has a non-sensingregion where the forward and backward movement of either the endoscopeor the treatment tool does not interlock with the forward and backwardmovement of the other and a sensing region where the forward andbackward movement of either the endoscope or the treatment toolinterlocks with the forward and backward movement of the other.
 16. Asurgery system comprising: an overtube that has a distal end, a proximalend, and a longitudinal axis and holds a treatment tool and an endoscopeso as to be movable forward and backward in a direction of thelongitudinal axis, the overtube having an endoscope holding part thathas an endoscope holding surface for holding the endoscope, and atreatment tool holding part that has a treatment tool holding surfacefor holding the treatment tool; and an endoscope that is inserted intothe overtube and has a held surface held by the endoscope holdingsurface, the endoscope having a gravity center position at a positiondeviating from the central axis of the endoscope, wherein a rotationalmoment, resulting from gravity, about the central axis in the gravitycenter position of the endoscope is greater than a friction moment,about the central axis, resulting from a frictional force between theendoscope holding surface and the held surface.
 17. The surgery systemaccording to claim 16, wherein the overtube has a movable body that ismovable in a direction of the longitudinal axis inside the overtube, andwherein the movable body has an endoscope locking part to which theendoscope holding part is locked, and a treatment tool locking part towhich the treatment tool holding part is locked.
 18. The surgery systemaccording to claim 17, wherein the movable body has a non-sensing regionwhere the forward and backward movement of either the endoscope or thetreatment tool does not interlock with the forward and backward movementof the other and a sensing region where the forward and backwardmovement of either the endoscope or the treatment tool interlocks withthe forward and backward movement of the other.
 19. The surgery systemaccording to claim 16, further comprising: an outer sheath that has adistal end opening and a proximal end opening and has an insertionpassage through which the overtube is inserted from the proximal endopening so as to be rotatable around the longitudinal axis.
 20. Asurgery system comprising: an overtube that has a distal end, a proximalend, and a longitudinal axis and holds a treatment tool and an endoscopeso as to be movable forward and backward in a direction of thelongitudinal axis, the overtube having an endoscope holding part thathas an endoscope holding surface for holding the endoscope and allowingcircumferential rotation of the endoscope about a central axis of theendoscope, and a treatment tool holding part that has a treatment toolholding surface for holding the treatment tool; and an endoscope that isinserted into the overtube, the endoscope having an insertion part thathas a distal end, a proximal end, and a central axis in a direction ofthe longitudinal axis, a cord part provided on a proximal end side ofthe insertion part, a connecting part that connects the insertion partand the cord part to each other, an image pick-up element provided on adistal end side of the insertion part, a held surface provided at theinsertion part and held by the endoscope holding surface, a rotationalmoment application part that applies a rotational moment around thecentral axis of the insertion part to the image pick-up element, whereina center of gravity of the rotational moment application part is at aposition eccentric from the central axis of the insertion part.